While New York’s gay couples are lining up to get hitched, straight ones are increasingly untying the knot.

Divorce filings are up 12 percent since the state last October adopted no-fault separations, which allows couples to split without having to prove why.

“It’s still going to the dentist,” said lawyer Raoul Felder. “But now you go to a painless dentist. There’s a certain percentage of people who do it now that wouldn’t have before.”

There were 37,015 divorce filings statewide from October 2010 through this May, compared to 33,160 in the year-ago period, according to court data.

Under New York’s former system, husbands and wives had to prove grounds for dissolving the marriage by providing embarrassing, and often false, testimony.

“The Ten Commandments say, ‘Thou shalt not commit adultery,’ ” Woody Allen once quipped. “But New York state says you have to.”

Divorce is also less expensive as a result of the change.

Lawyers are spending fewer billable hours deciding whether adultery, cruelty or, most popularly, the refusal of sex for more than a year was to blame for the breakup, attorneys said.

“People didn’t want to deal with that embarrassment. This is a much easier process,” said lawyer Fred Siegel. “You would have to spend significant energy and money long before you even got to the economics.”

According to an analysis by The Business Review, attorneys so far are not reporting a decrease in revenue — perhaps because of the increased filings.

Also playing a role in the increase are provisions that ensure that the wealthier spouse provides legal fees, attorneys said.

That rule also went into effect last October.

“When people want to get divorced, they’re going to get a divorce. All no-fault did was stop forcing people to commit perjury,” divorce lawyer Sue Moss said.

But attorney Bernard Clair said the increase is more likely due to changes in the economy.

“This has nothing to do with no-fault,” he said. “There’s been the sense that the economy is now getting a little better.”